To what extent is the narration cited by Imam al-Bukhari in "Al-Adab al-Mufrad" from Mu'awiyah bin Qurrah, concerning his supplication for his son Iyas, authentic?

Al-Bukhari narrates in "Al-Adab Al-Mufrad" the story of Mu'awiyah ibn Qurrah when his son Iyas was born. He invited a group of the Prophet's companions (peace be upon him), fed them, and they supplicated for him. Mu'awiyah then asked them to say "Amen" to his supplication for his son, asking for abundant blessings in his religion and intellect, and he later witnessed the effect of this supplication in his son Iyas. This chain of narration is sound, and its narrators are trustworthy. However, it is not a hadith directly attributed to the Prophet (peace be upon him); rather, it is from the words of the noble Tabi'i Mu'awiyah ibn Qurrah and his supplication for his son Iyas, who later became a great scholar, judge, and jurist. It is probable that this was due to the blessing of his father's supplication for him. Sheikh Abdullah Al-Sa'd indicates that this demonstrates the blessing of supplicating for children with righteousness and blessings, and that it is part of the Prophet's guidance (peace be upon him) to supplicate for blessings.